Mrs Ratcliffe, who has dual British-Iranian nationality, had been on holiday visiting her parents in Tehran. The authorities kept Gabriella’s British passport, meaning that the child is stranded inside Iran in the care of her grandparents.

The little girl passed her second birthday last Saturday without either her mother or her father, Richard Ratcliffe, who is in Britain. During the last phone call she was allowed to make from jail on June 5, Mrs Ratcliffe voiced the hope that she would be freed in time for her daughter’s birthday.

“I think she’s probably back in solitary confinement,” said Mr Ratcliffe. “Everything that we know is consistent with her being back in solitary. It’s really very concerning. She was very clear that she really hoped to be out in time for Gabriella’s birthday.”

Richard Ratcliffe leaves a birthday card for his daughter, Gabriella, outside the Iranian Embassy in London. Gabriella is now stranded inside Iran where her mother, Nazanin, was arrested on April 3.Credit:
PA

Immediately after her arrest, Mrs Ratcliffe was taken to a prison in Kerman province, 600 miles south-east of Tehran, and placed in solitary confinement. She was then transferred to a group cell on May 18 and allowed to see her parents and Gabriella.

But Mr Ratcliffe, a 41-year-old accountant from Fleet in Hampshire, is no longer sure where she is being held. “It feels like it’s a demonstration of power and control,” he said. “She really had built all her hopes up to be released in time for Gabriella’s birthday.”

Mrs Ratcliffe, who has lived in Britain since 2007, is a programme manager for the Thomson-Reuters Foundation, the charitable arm of the news agency. The regime is deeply suspicious of Iranian nationals who also carry Western passports. Exactly why Mrs Ratcliffe is being held or what offence she is accused of committing remains unclear.

Nazanin Zaghari-Ratcliffe with her daughter, Gabriella. Mrs Ratcliffe is believed to be in solitary confinement inside an Iranian prison.Credit:
Richard Ratcliffe